Oil-filled electrothermal warmers are referred to as electrothermal oil heaters now. The electrothermal oil heaters, as environmentally friendly, noiseless and other advantages, have been widely used in the world. There are 40 million electrothermal oil heaters manufactured every year. Such an electrothermal oil heater is generally assembled by a plurality of radiating fins, with gaps formed between the radiating fins, connected to each other via hollow connecting sleeves at an upper end and a lower end of the radiating fins. There is a cavity, filled with heat transfer oil, formed on each of the radiating fins. An electrical heating assembly is immersed in the heat transfer oil, and energy is transferred by heating the heat transfer oil. However, such a radiating fin has a limited radiating area and small heat supply range, and hence, the heat diversion effect is not very ideal. Merely increasing the superficial area of the radiating fin will increase energy consumption and expand space occupation, and also will degrade the mechanical strength of the radiating fin.
In China Utility Model Patent CN 200920141585.3, publicized on Jan. 20, 2010, a radiating fin for a warmer is disclosed, including a radiating fin, with a hollow connecting sleeve being respectively provided on an upper portion and a lower portion of the radiating fin, characterized in that both sides of the radiating fin are flanged symmetrically. In this technical solution, both sides of the radiating fin are flanged symmetrically, so that the radiating area of the radiating fin can be increased without increasing the space occupation thereof. Furthermore, the design of flanging enables formation of a chimney radiating channel between two adjacent radiating fins, thus to improve the radiating efficiency of the radiating fin. However, for an electrothermal oil heater in this solution, hot air will be mostly dispersed above the oil heater, and as a result, the heat radiating radius around sides of the oil heater will be significantly reduced. When there is an airer or something else placed above the oil heater, the convection of the radiating channel will be greatly impeded, and the radiating efficiency of the oil heater will be influenced. Consequently, the temperature interior of the oil heater is too high and the service life of the oil heater will be shortened.